题目内容：

短文改错

About a month ago, I was walking alone on the beach in the evening. I have already finished my homework, and I wanted to relax. Suddenly, I saw two children stand on the beach. They seem to have found something made of metal, which was big and reddish­brown. When I took a look at it, I knew immediate that it was an old bomb! I told them to move away the bomb. Fortunately, I had a mobile phone around with me, so I called the police and told them that had been found. About 15 minutes late, the police arrived. I was praised for it but then I went home. The next day, I heard that the police had blown the bomb up. It had been on the sand for over 60 years!